The present invention relates to spools for carrying such things as wire and cable, and more particularly to primarily wooden spools which are held together by tie rod assemblies.
Wooden spools are used to support and transport large quantities of wire, cable and other such cordage. Strength of the spool is often very important as the weight of the material carried by the spool is typically very large. As illustrated in FIG. 1, a prior art wooden spool 10 typically comprises two planar wood flanges 12 spaced apart in generally parallel relationship and a central barrel 14 extending transversely therebetween. To tie and hold these spool components together, a tie rod assembly 16 is utilized that comprises elongate bolts 18 and t-nuts 20. To assembly the spool, the ends of the barrel 14 are first received in diametrically opposed grooves 22 in the flanges. Then, the bolts 18 are inserted through diametrically opposed holes 24 in the flanges. Each bolt 18 extends through the barrel 14 and includes a threaded end 26 that projects axially outward from the outside face of one of the flanges. The t-nuts 20 are pressed into the wood and the bolts are screwed into the t-nuts until each t-nut 20 engages the adjacent flange and the hexagonal head 28 of each bolt firmly engages the other flange coacting against the t-nut.
The prior art spool illustrated in FIG. 1 has worked satisfactorily for many years and is well accepted in the industry. However, it will be appreciated by those skilled in the art, that the spool can comprise a noticeable portion of the overall cost of producing a sellable spool of wire. The reason is that the wire carried by the spool may be a relatively inexpensive material which makes it desirable to provide an inexpensive spool. As will be readily appreciated by those skilled in the art when viewing the present invention, the inventor of the present application has realized that there are several cost drawbacks associated with the materials and assembly method of prior art wooden spool assemblies.
It is therefore an objective of the present invention to reduce the raw material costs associated with the tie rod assemblies for wooden spools.
It is another objective of the present invention to provide a more cost efficient way to assemble a wooden spool.
It is another objective of the present invention to accomplish the above objectives while maintaining or possibly improving the satisfactory strength characteristics of prior art wooden spools.
In accordance with these and other objectives, the present invention is directed towards a less costly spool that comprises a pair of spaced apart end flanges, a barrel transversely between the flanges, and a novel and less expensive tie rod assembly. The novel tie rod assembly includes a plurality of rods that have a bent end or otherwise deformed or enlarged end, and a plurality of retaining rings that are pressed axially on the other ends of the rods. Suitable retaining rings include those with axially offset inner and outer circular edges with a curved cross section therebetween.
There are several advantages of the novel tie rod assembly. One advantage is that formed threading is not necessary in the ends of the tie rods. This provides for inexpensive raw materials as the costly step of forming threads into the ends of the tie rods can be eliminated. The present invention also provides for an easier assembly operation as rotation of the nuts or the tie rod is not necessary during spool assembly. Because no rotation is needed, a hexagonal head at the other end does not need to be formed, thereby also reducing material costs of the tie rods. A further advantage that is achieved when using the preferred method of assembly is that the retaining rings can be pressed into the wood material of the flanges such that the retaining rings are maintained in tight constant engagement with the corresponding flange, which in turn, causes the inner edges of the retaining rings to apply continuous gripping pressure against the outer diameter of the tie rods.
The present invention is also directed toward a new method of assembling a wooden spool. According to the new method, a wooden spool assembly including the novel tie rod assembly is placed between two pressing dies, with the retaining rings yet to be pressed on the free ends of the tie rods. According to the method, the bent or otherwise enlarged ends of the tie rods are received in locating recesses in the base die. The top die includes engaging pins aligned with the locating recesses for pressing the retaining rings on the free ends of the tie rods. The dies are moved axially together to axially press the retaining rings on the free ends of the tie rods. During pressing, the dies are translated axially preferably until the spool is in slight axial compression between dies. When released, the upper wooden flange of the spool engages outer peripheral edge of the retaining rings which in turn causes the inner peripheral edges of the retaining rings to apply radially inward force on the respective tie rods. This advantageously provides a desirable strength feature and prevents slack between the barrel and the flanges. This also achieves an easier assembly operation.